Noord-Holland (North Holland) contains the largest city in the Netherlands is the Dutch capital Amsterdam. Nevertheless, the provincial capital is Haarlem. The broad peninsula is located between the North Sea, the Wadden Sea, the IJsselmeer, and the Markermeer. More than half of the province is reclaimed polder, in other words land which is located below sea level and way reclaimed by collecting mud in the tides and finally building a dam around. It is continually pumped by windmills to get the rainwater out. These are terrible conditions for underground structures, so the only listed sight are casemates, which is not "really" underground.